protons‚ 44 neutrons‚ 35 electrons (1) 81Br 35 protons‚ 46 neutrons‚ 35 electrons (1) 2 (iii) (1s2)2s22p63s23p63d104s24p5 (1) 1 [4] 2. (i) iodide has been converted to iodine (1) (with correct use and spelling of iodide and iodine) The 1st experiment shows that bromine is more reactive than iodine (1) The 2nd experiment shows that chlorine is more reactive than bromine (1) Accept 1 mark for 2nd and 3rd marking points if the
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AN IODINE CLOCK REACTION PURPOSE To investigate the kinetics of the reaction that occurs between iodide and persulfate ion. You will: (1) determine the rate law‚ (2) determine the numerical value of the rate constant at room temperature‚ (3) explore the effect of temperature on the reaction and determine the activation energy (Ea)‚ and (4) investigate catalytic activity of selected metal ions on the reaction. INTRODUCTION Reaction times vary from picoseconds (10-12 seconds) to years. It is
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beaker. Mix the contents well. Transfer the contents of the beaker to a 250 ml volumetric flask and make up the volume to the graduation mark‚ observing all of the usual procedures. The addition of sulphuric acid is vital as it prevents the Fe 2 ions from reacting with Prepare the potassium permanganate solution. Weigh out an approximate amount of KMnO 4 ‚ in a beaker‚ enough to make an approximately 0.02 M solution. Dissolve in dilute sulphuric acid‚ transfer and make up the solution in the
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A123 Systems History of Lithium-Ion Batteries Rechargeable battery evolution accelerated as the world transitioned to instruments enabled by silicon microchip technology from those of bulky electrical components. Mobile devices were designed to be powered by lightweight energy storage systems. The development of batteries for this rapidly evolving market was challenging: • The nickel cadmium battery had been the only option for modern electronics for many years. It was a great improvement over
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Alkali Metals Introduction Alkali metals refer to six elements belonging to the Group IA of the long form of the Modern Periodic Table‚ viz. Lithium (Li)‚ Sodium (Na)‚ Potassium (K)‚ Rubidium (Rb)‚ Cesium (Cs) and Francium (Fr). Fr is a radioactive element. These elements are called so because they form strongly alkaline oxides and hydroxides. Electronic Configuration of Alkali Metals Each of the alkali metals has one electron in their outermost (valence) shell‚ which is just outside an inert
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ascorbic acid solution. Brown iodine can be easily reduced by acidified ascorbic acid to form colourless iodide ion: ← Equation I The excess iodine is then back titrated by standard sodium thiosulphate solution‚ by using a burette and starch solution (used as end point indicator) Similarly‚ iodine can also be decolourized by thiosulphate ion: 2S2O32- + I2 → S4O62- + 2I-
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GCSE CHEMISTRY High Demand Questions THE PERIODIC TABLE QUESTIONSHEET 1 The boxes represent particles of different gases. One box shows the particles of elements in group 0 (group 8). A (a) (i) B C D What name is given to group 0 (8) elements? (ii) Name two elements from group 0. ......................................................................................................................................................................... [2] (b) (i) Which box
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of the concentration of each solution and the temperature at which the reaction takes place. The experiment focuses primarily on the reaction between the ions bromate and iodide. 6I-(aq) + BrO3-(aq) + 6H+ 3I2(aq) + Br-(aq) + 3H2O(l) (1) In part one to determine the rate order of the ions the rate law of reaction is used as well as to find the rate constant (k). Rate Law of Reaction Rate= k[I-]x[BrO3-]y[H+]z
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protonated OH group is a good leaving group. Step 1: CH3 CH3-C-CH3 + H+ HO CH3 CH3-C-CH3 H2O+ Fast u u In the second step‚ water molecule is lost with the formation of a carbonium ion. This is the rate determining step. CH3 CH3 u Step 2: Slow CH3-C-CH3 CH3-C-CH3 + H2O + H2O+ In the final step carbonium ion loses proton from its adjacent carbon atom which results in more stable alkene. The anions of the acid or another alcohol molecule will function as a base and facilitate loss of proton.
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THERMOCHENISTRY Index 1.0 Introduction | | | | | | | | 1 | 2.0 Enthalpy Changes | | | | | | | 2‚3 | 2.1 The Standard Conditions For Calculating Enthalpy Changes | | | | 3.0 Hess’s Law | | | | | | | | 4‚5 | 3.1 The Applications of Hess’s Law | | | | | | 4.0 Standard Molar Enthalpy Change of Formation‚ ΔHof | | | | 6‚7 | 4.1 The Stability of A Compound | | | | | | | 4.2 Using ΔHof
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